Compressed tampons have certain advantages over noncompressed tampons relating essentially to their increased absorbent material per unit volume, and accompanying ease of insertion relative to the amount of absorbent.
A radially compressed tampon, for instance, when in place in the vagina, radially expands with the uptake of menstrual fluid and may, in fact, swell to its original uncompressed volume or, in some instances, to an even higher volume.
Radially compressed tampons may be designed for digital insertion or for use with insertion aids such as the traditional telescoping tube type tampon applicator or the stick tampon applicator. In any event, after compression, the tampon pledget tends to reexpand to its original dimension. To overcome this tendency, heat-setting has been utilized. The application of heat is designed to "set" the tampon in its compressed state. Conventional heat-setting, however, has some distinct disadvantages. First and foremost of these is the substantial increase in manufacturing time necessary to subject the tampons to an amount of heat necessary to obtain some level of set. If relatively high temperatures are used in an attempt to speed the process, the outside of the tampon which is a dense, compacted material is heated substantially faster than the inside, and the outer surface may be degraded and lose its absorbent characteristics.
This invention provides a process for rapid and uniform heat-setting of a tampon containing fibrous absorbent as well as a radially compressed tampon having certain unique characteristics.
For purposes of this invention, the term "fibrous" refers to tampon absorbent material derived from traditional cellulosic sources such as wood pulp cotton linters, etc. as well as the rayon derived absorbents and certain synthetic absorbent polymeric fibers and is meant to include various mixtures of absorbent materials and blends which, for example, may include superabsorbents. The term is specifically used to differentiate between tampons which utilize a foam or a foam in combination with superabsorbents as the absorbent material. The teachings of this invention have no particular application to such nonfibrous absorbent materials.